Field
The present disclosure relates generally to an interface between processors and a peripheral devices and, more particularly to voltage mode drivers for transmitting multi-wire, multi-level differential signals over a plurality of conductors.
Background
In multi-signal data transfer, differential signaling is sometimes used to transmit information. For example, an N-factorial (N!) communications interface may be configured using a termination network such that differential signals may be transmitted on each of a plurality of different pairs of N wires or connectors available for communication between devices. The termination network has N termination impedances, which are typically resistive, and each termination impedance couples its corresponding wire to a center, null point of the termination network. The current flows attributable to each N! differential driver cancel at the null point, and the signaling state of each wire may be expressed as a signaling voltage and determined as a product of the sum of currents flowing in the wire and the termination impedance couple to the wire as observed at a receiver.
In certain implementations of an N! interface, the use of current sources in an N! differential driver may be disadvantageous, including in devices that employ higher frequency signaling or that are subjected to limited power budgets.